Evaporator



28, 1937. E, L, L LY 2,103,521

EVAPORAT OR File d OGtJ 50, 1936 r 2 Sheets-Sheet 1 Fig 1 III (MI INVENT OR.

Edgar Lluly ATTORNEY.

Dec; 28, 1937. EL U 2,103,521

' 'EVAPORATOR Filed Oct. 30, 1936 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY.

patted o... 28, 1931 2,103,521

UNITED STATES PATENT OFFICE EVAPOBATOR Edgar Lionel Luly, London, England, assignor to The Babcock & Wilcox Company, Newark, N. J., a corporation of New Jersey Application October 30, 1936, Serial No. 108,341 In Great Britain September 3, 1935 6 Claims. (01. 159-31) This invention relates in general to the conapplication, arranged coaxially with said casing. struction and operation of vapor generating ap- An inverted frusto-conical baflie Hi arranged coparatus. While my invention is particularly apaxially with the sprayer head extends downplicable to evaporators used for concentrating wardly from the casing top section II to a level '5 liquors, such as chemical solutions. it is also below the sprayer head level.

applicable to evaporator-s for boiler feed water. With the described arrangement wet vapor lib- As generally used in concentrating chemical erated from the body of liquid in the bottom solutions, such evaporators have the disadvan-V by any suitable heating means would-ascend and tage that a certain proportion of the chemical pass around the lower end of the baflie I6 to.

"10 contents of the liquor is carried up by the satuthe zone or activity of the sprayer head 15. A

rated or superheated vapor arising from the suitable washing liquid is supplied to the sprayer boiling liquor into the vapor pipework with a head as hereinafter described and discharged in consequent loss of chemicals, and in multiple a spray through which the ascending vapor must effect evaporators, a loss in heat transfer efiipass to .reach the separator sections i3. Parciency and loss of time due to stoppage for ticles of liquid and solids in suspension are sepacleaning. rated from the gases and added to the washing These disadvantages may be overcome by the liquor, while the dry and clean vapor passes out provision in the upper portion of the evaporator through the pipe l2. Where a mixture of vapors of a spray of suitable washing liquid directed is generated, some of the vapors can be removed across the path of the uprising vapor so that by using a suitable absorbing, washing liquid. certain constituents thereof'will be removed by In accordance with my invention the desired a washing action prior to the passage of the results are attained by providing at a suitable vapor to the outlet. If desired a liquid separatposition between the surface of the body of cheming device may also be provided above the liquor ical liquor and the sprayer head l5, a distributor spray and prior to the outlet. cone 20 of suitable diameter and of a material In dealing with chemical solutions, however, capable of withstanding the corrosive properties, it is highly desirable that the washing liquid if any, of the liquor and/or vapor contacting be prevented from mixing or coming into contherewith. The distributor is bounded at its tact with the main body of liquor under treatlowest extremity by a relatively short dependment. A main 'object of my invention is to ing hollow cylinder or skirt 2| which may be provide an evaporator construction and arrangesolid or perforated. The skirt 2| depends into ment in hich such mixing or contacting of the the upper portion of an annular collecting chamwashing liquid with the liquor under treatment ber 22 shown as formed within the evaporator is revented. casing by a symmetrically arranged annular In the drawings: -L-shaped plate 23 secured to the casing l0.

Fig. 1 is a somewhat diagrammatic sectional The collecting chamber 22 is provided with" elevation of an evaporator incorporating my ina make-up supply connection 25 and a blowvention; and down connection 26 which may deliver to waste,

' 0 Fig. 2 is a similar view of a modification. a recovery tank or a preheater for the make-up.

The evaporator shown in Fig. 1 is formed by The sprayer head l5 ec i t liquid pp y a vertically elongated cylindrical casing l0 al'daptm h o lec ing chamber through a p 21 ed to contain a body of chemical liquid in the Opening to t bottom f the c be a ci ubottom thereof and having a tapered top sec- 1 la'ting p p and p pe A flo 30 1 rtion "ll through which extends a central vapor ranged in the Collecting chamber o o r a outlet pipe l2 tapering towards its open lower valve 3| located in an overflow pipe 32 disend. At the lower end of the pipe I! anddischarging to waste, a recovery tank or a preheater charging thereto is arranged a gas and liquid for the make-up, and limit the maximum liquid separator of the type disclosed in a prior applilevel in the chamber. A heating coil 33 is concation of James Fletcher et 9.1., Serial No. 7,188, ventionally shown in the lower part of the evapofiled Feb. 19, 1935, having corrugated plate separator to provide means for vaporizing the surratcr sections i3 in a cruciform arrangement. rounding liquid;

- The separator sections have a common drain In operation the vapors generated in the botchamber it which is drained by an aspirating tom of the evaporator ascend in the casing, flow sprayer head l5, also of the type shown in said over the upper end of the bailie 23 and below the the casing. The direction of the vapor flow is again changed by the baflle l6 before the vapor reaches the separator sections l3. The washing liquid is drawn from the collecting chamber by the pump 28 and delivered to the spraying device I5. The spray discharged is such that the rising vapor will be compelled to pass through it on its way to the separating sections l3 and outlet pipe l2. With the casing ID of circular cross-section, a finely divided conical spray is preferable. The falling spray descends onto the subjacent distributor cone 20, and flows over the lower edge thereof and down the depending skirt 2|, and so into the collecting chamber, the cycle thereupon recommencing. The vapors rising from the surface of the pool of chemical so lution are thus constrained to pass successively through a plurality of washing liquid curtains formed by the spray falling from the spraying head and by the spray falling from the distributor cone. The rising vapors thus pass through a progressively "cleaner washing liquid so that the final washing is effected by liquid which is at the lowest concentration. In other words the systemmay be stated to work on the contraflow principle in that the vapor most heavily charged with chemicals will contact with the washing liquid when it is at its greatest concentration.

Make-up washing liquid is supplied to the collecting chamber to compensate for that discharged through the overflow pipe 32-and the blow-down connection 26, the blow-down provisions being essential to limit the concentration of the washing liquid in the collecting chamber. A certain amount of condensation of vapor will take place, thus reducing the amount of make-up to be added. Both the overflow and the blowdown liquid may thus be utilized for preheating the make-up washing liquid and then if desired the chemical contents thereof may be recovered by suitable means.

In the modification shown in Fig. 2 the annularcollecting chamber is shown as located around the external periphery of the casing l instead of within the casing, as shown in Fig. 1. In the Fig. 2 construction, the collecting chamber is closed at both its lower and upper ends, and communicates with the interior of the evaporator at its inner side through vertically elongated slots 40 formed in that section of the casing Ill. The skirt of the distributor cone is omitted in this construction and a frusto-conical baflle 4| arranged at the lower ends of the slots 40 coaxial with the cone and its upper end smaller than the lower periphery of the cone 20, to provide a sinuous flow path for the ascending vapor and facilitate the passage of the washing liquid through the casing slots 40 into the external collecting chamber 22. The operation is otherwise similar to that in Fig. 1.

Both evaporator constructions described effectively prevent mixing of the washing liquid with the main body of liquid in the evaporator, while permitting an intimate and efiicient washing of the vapor generated.

While in accordance with the provisions of the statutes I have illustrated and described herein the best forms of my invention now known to me, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention distributor cone skirt 22 to the upper part of may sometimes be used to advantage without a. corresponding use of other features.

I claim;

1. An evaporator having a cylindrical casing constructed to contain a pool of vaporizable liq uid in the lower part thereof and having a vapor outlet from the upper part thereof, a sprayer head above said pool arranged to downwardly discharge a conical liquid spray in said casing, a distributor cone symmetrically arranged relative to and below said sprayer head and having its lower end spaced from the sides of said casing for the passage of ascending vapor, a separate annular collection chamber arranged to receive and collect liquid dropping from said distributor cone, means for delivering liquid from said collecting chamber to said sprayer head, a blowdown connection for said collecting chamber, and. means for supplying make-up liquid directly to said collecting chamber.

2. An evaporator having a cylindrical casing constructed to contain a pool of vaporlzable liquid in the lower part thereof and having a. vapor outlet from the upper part thereof, a gas and liquid separator in said casing opening to said outlet, a sprayer head below said separator arranged to downwardly discharge a conical liquid spray in said casing, a distributor cone symmetrically arranged relative to and below said sprayer head and having its lower end spaced from the sides of said casing for the passage of ascending vapor, a separate annular collection chamber arranged to receive and collect liquid dropping from said distributor cone, means for delivering liquid from said collecting chamber to said sprayer head, and liquid level control means in said collecting chamber.

3. An evaporator having a cylindrical casing constructed to contain a pool of vaporizable liquid in the lower part thereof and having a vapor outlet pipe projecting downwardly within the upper part thereof, a gas and liquid separator in said casing opening to said outlet, a. sprayer head below said separator arranged to downwardly discharge a conical liquid spray in said casing, an inverted frusto-conical balile surrounding said sprayer head at the sides of said casing, a distributor cone symmetrically arranged relative to and below said sprayer head and having its lower end spaced from the sides of said casing for the passage of ascending vapor, a separate annular collection chamber arranged to receive and collect liquid dropping from said distributor cone, and means for delivering liquid from said collecting chamber to said sprayer head.

4. An evaporator having a cylindrical casing constructed to contain a. pool of vaporizable liquid in the lower part thereof and having a vapor outlet pipe projecting downwardly within, the.

upper part thereof, a gas and liquid separator in said casing opening to said outlet, 9. sprayer head below said separator arranged to downwardly discharge a conical liquid spray in said casing, an inverted frusto-conical baflle surrounding said sprayer head at the sides of said casing, a distributor cone symmetrically arranged relative to and below said sprayer head and having its lower end spaced from the sides of said casing for the passage of ascending vapor, a separate annular collection chamber arranged to receive and collect liquid dropping from said distributor cone, means for delivering liquid from said collecting chamber to said sprayer head, liquid level control means in said collecting chamher, a blow-down connection for said collecting uid directly to said collecting chamber.

5. An evaporator having a cylindrical casing constructed to contain a pool of vaporizable liquid in the lower part thereof and having a vapor outlet in the upper part thereof, a gas and liquid separator in said casing opening to said outlet, a. sprayer head below said separator arranged to downwardly discharge a conical liquid spray in said casing, a distributor cone symmetrically arranged relative to and below said sprayer head and having its lower end spaced from the sides of said casing for the passage therebetween of ascending vapor, and a separate annular collection chamber arranged to receive and collect liquid dropping from said distributor cone.

6. An evaporator having a cylindrical casing constructed to contain a pool of vaporiz'able liquid in the lower part thereof and having a vapor outlet in the upper part thereof, a gas and liquid separator in said casing opening to said outlet,

9. sprayer head ,below said separator arranged to downwardly discharge a conical liquid spray in said casing, an inverted frusto-conical baflle surrounding said sprayer head at the sides of said casing, a distributor cone symmetrically arranged relative to and below said sprayer head and having its lower end spaced from the sides of said EDGAR LIONEL LULY. 

